Yin-Yang theory is a unique philosophical theory in ancient China, which holds that all things and phenomena are formed by the interaction of the two basic forces of Yin and Yang. The commentary of “Book of Changes” says that Yin and Yang constitute Dao (of Daoism). Here, Dao represents the universal law of things.

Yin and Yang initially referred to the direction of sunlight, with the side facing the sun being Yang and the side backing the sun being Yin. Later, it was used to describe the heat and cold of the climate, the up and down, left and right, inside and outside, the movement of the state of restlessness and tranquility and so on.And then improve this understanding, that things positive and negative sides are both opposing each other, but also dependent on each other, and anything, but also in constant motion and change. This summarizes the basic theories of Yin and Yang opposition, Yin and Yang dependence, Yin and Yang growth, Yin and Yang transformation, etc., which are used to understand and explain the existence and change of things in the whole universe.

Yin-Yang theory runs through all aspects of the theoretical system of Chinese medicine, which is used to explain the organizational structure of the human body, physiological activities, the occurrence and development of diseases, and guides clinical diagnosis and treatment. Chinese medicine believes that the human body is an organic whole, which is full of the relationship between Yin and Yang, and uses the theory of Yin and Yang opposites and dependencies to explain the contradictory, antagonistic and unifying relationship of the human body's organization and structure. The physiological activities of the human body is very complex, in general terms of Yin and Yang, the material is Yin, function is Yang. Various functional activities of the human body (Yang) of the production, inevitably consume a certain amount of nutrients (Yin), and nutrients (Yin) of the chemical production, but also must rely on the functional activities of the organs and consume a certain amount of energy (Yang). In the process of metabolism, whether it is between substances or substances and functions, there is a relationship between the same transformation. According to Chinese medicine, the relationship between yin and yang in human physiology is one of antagonism and elimination, as well as one of dependence and transformation. In the process of this series of complex physiological activities, maintaining a relative state of balance is an important condition. In addition, the theory of Yin and Yang is also used to explain the pathological changes in the human body. The occurrence and development of human diseases are related to both positive and evil, and the struggle between evil and positive leads to the destruction of the balance and coordination of Yin and Yang in the human body, thus resulting in an imbalance of Yin and Yang (dysfunction). Therefore, although the pathology of the human body is complex, the general outline is no more than an excess of Yin and a decline of Yang and an excess of Yang and a decline of Yin.

The five elements theory is another important theory of Chinese medicine. The five elements include wood, fire, earth, gold and water. On the one hand, the doctrine of the five elements believes that everything in the world is composed of these five basic substances, which is a correct answer to the origin of the world; on the other hand, it believes that everything is not isolated and static, but maintains a coordinated balance amidst the movement of constant mutual birth and mutual restraint.

The five elements theory is based on the characteristics of each element and is abstractly applied to correspond to specific phenomena in nature. In Chinese medicine, the characteristics of the five elements are used to analyze the attributes of the five elements in human tissues and organs, to analyze the physiological connection among the five organs by the birth and restraint of the five elements, and to explain the interplay between the five organs and their pathologies by the multiplication and insult of the five elements, and by the interplay of the five elements and their interactions with the mother and the son, and on this basis, they are used in the diagnosis and treatment of diseases. For example, wood represents the liver and gallbladder, fire corresponds to the heart and small intestine, earth is associated with the spleen and stomach, gold represents the lungs and large intestine, and water involves the kidneys and bladder. The five elements theory emphasizes the symbiotic relationship between these elements, i.e. wood begets fire, fire begets earth, earth begets gold, gold begets water, water begets wood; wood begets earth, fire begets gold, earth begets water, gold begets wood, and water begets fire. This cyclic relationship helps to maintain the body's internal balance and harmony, if the five elements are out of balance, it may lead to abnormalities in the functioning of the relevant internal organs, which in turn leads to a variety of health problems.

The theory of yin and yang and the five elements provide a unique perspective for us to understand health and disease, and in the practical application of Chinese medicine, the two are usually used in combination, such as the internal organs can be divided into yin and yang, and the relationship between the five internal organs can be explained by the theory of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements of the five elements. Chinese medicine through the imbalance of yin and yang and the five elements of the phases of the relationship between the analysis to carry out a comprehensive diagnosis and treatment, through the identification of a person's physique and symptoms belong to what kind of yin and yang imbalance, and combined with the five elements of the theory of the functional state of the internal organs, so as to formulate a personalized treatment plan.